Shoulder
The shoulder trades stability for mobility: a large ball sits on a small, shallow socket, so muscles—especially the rotator cuff and the shoulder-blade muscles—do much of the work of keeping it centred.
Anatomical structures
Glenohumeral joint
The main shoulder joint—a ball (humeral head) and shallow socket (glenoid of the shoulder blade).
Acromioclavicular (AC) joint
Small joint where the collarbone meets the acromion.
Scapulothoracic region
The functional "joint" where the shoulder blade glides over the rib cage.
Rotator cuff
Four muscles and their tendons—supraspinatus, infraspinatus, teres minor and subscapularis.
Supraspinatus
Rotator cuff muscle above the spine of the shoulder blade.
Infraspinatus
Rotator cuff muscle on the back of the shoulder blade.
Teres minor
Small rotator cuff muscle below infraspinatus.
Subscapularis
The largest rotator cuff muscle, on the front surface of the shoulder blade.
Deltoid
The large rounded muscle that caps the shoulder (front, middle, back parts).
Long-head biceps tendon
Tendon of the long head of biceps brachii.
Glenoid labrum
A fibrocartilage rim around the shoulder socket.
Shoulder capsule and ligaments
Fibrous sleeve around the joint, thickened into glenohumeral ligaments.
Subacromial bursa
A thin fluid sac that lets tendons glide.
Acromion
Bony projection of the shoulder blade forming the roof of the shoulder.
Scapular stabilisers
Trapezius (upper, middle, lower), rhomboids, serratus anterior and levator scapulae.
Serratus anterior
Saw-toothed muscle on the side of the rib cage.
Conditions
Rehab protocols
- Shoulder Pain PDF 360
- Shoulder Instability PDF 397
- Frozen Shoulder (Adhesive Capsulitis) PDF 420
- Biceps Tendinopathy PDF 440
Tests
- Painful arc self-observation self
- Overhead reach comparison self
- Hand-behind-back reach comparison self
- Outward-rotation comparison self
- Night pain and sleep-position log self
- Apprehension awareness (do not provoke) self
- Empty can (Jobe) test clinical
- External rotation lag sign clinical
- Drop arm test clinical
- Hawkins–Kennedy test clinical
- Neer test clinical
- Painful arc (clinical) clinical
- Apprehension and relocation tests clinical
- Sulcus sign clinical
- O'Brien active compression test clinical
- Speed's test clinical
- Yergason's test clinical
- Passive external rotation range clinical
- Ultrasound and MRI imaging
Exercises (48)
Prevention
Keep the phase 3 exercises from this region’s protocols in your routine 2–3× a week, build training load gradually and warm up specifically for your sport. Injury prevention principles →